Flying structure

Please help me, I built a structure in mcreat, set it up, but it will spawn flying in the air, I read the forums and realized that it can be fixed using procedures, but neither in YouTube nor on the Internet I did not really find what I need, also I first put a structural block on the side. but also after reading on the Internet, I found out that it is better to put buildings in the middle at the bottom, but this also does not work! I ask those who know how to fix it, write to Discord zongg#3060 I will describe the problem in more detail

THANKS